Motherboard? Help?

This may seem like a dumb thing to ask, but I just need someone else to really think this is the problem. A couple weeks ago, I was sitting on my couch after I had gotten off the computer, and then screen went black, and the light on the monitor started to blink. All the fans in the case were spinning as well as the CPU fan, and HD had vibration as if it was running. At first I thought the computer went into hibernate and then locked up, but then after a reboot via the reset switch, the same thing happened. Multiple reboots later SSDD.....

Things ive done: Tried a new GPU, tried another PSU, went through the ram one at a time, reset the CMOS and Jumper, bought a new CPU.... so I know, i know the only thing left is the mobo, but do any of you have any other idea's before I do this, im sure Newegg is getting pissed that I keep RMA returning items just to troubleshoot my computer. The only heating issue would be my CPU, but ive replaced that so I can rule out heat.

Asus M2N SLI Deluxe, AMD 6000+, Zalman 9700, EVGA 7950GT KO superclocked, 4GB of XMS800 DDR2, 320GB Seagate HD, Audigy soundblaster, 500W Antec Earthwatts PSU(NEW)

Have you tried a different monitor? Have you tried it with just one stick of RAM?

While I doubt any of these are the issue, it is better to check before you RMA the MOBO.